KSTR
Major Contributor
...or just use the manual two-tone setup in REW, that is
Are people hearing the 2.8% distortion in the second video?
Are people hearing the 2.8% distortion in the second video?
I can definitely hear it over loudspeakers(don't have good headphones here). What does that mean?
This test is not scientific enough to draw any firm conclusions. I will produce some proper abx tests later. Rather this is just an indicator that for pures tones the results in the table I posted above seem reasonable. That with the worst case scenario (pure tones) we can hear harmonic distortion at surprisingly low levels.I can definitely hear it over loudspeakers(don't have good headphones here). What does that mean?
Not necessarily.According to the AES paper presented by @March Audio, it is within the realm of possibility that you can still perceive 2.8% HD2 at 96dB SPL with an 80Hz masker.
View attachment 98720
The prerequisite is, of course, that your loudspeaker itself delivers well below 2.8% HD2 at 80Hz and that the listening room (or objects) does not distort the result due to self-resonances.
But I honestly find it hard to imagine that in a normal listening room you can achieve results like under laboratory conditions (anechoic chamber?) - however, I do not know the test conditions in the AES paper.
First part is going to be to use tones and distortion profiles generated from the tests we have here on ASR.@March Audio what exactly are you planning to do in terms of an ABX test? Generate music files that are convolved with a transfer function resembling that of a high-distortion woofer?
FWIW, I did a similar (though even less formal) thing a while back, when I wanted to emulate the distortion performance of a few woofers I was trying to decide between for a speaker design, as well as to try to inform my decision about appropriate crossover points. I didn't have the programming skills to generate highly accurate models, but using VST plugins I did manage to produce roughly comparable levels and spectra of harmonic distortion to the drivers in question, with a similar (but not perfect) relationship between frequency, SPL and distortion level. Doing it in this way in DAW had the advantage of being able to easily filter the signal at a desired virtual crossover frequency, then pass only the operating range of the virtual driver through the distorting effect. It was also possibly to quickly and easily change the XO frequency or switch virtual drivers this way. There was some educated guesswork though in calculating the SPL of the headphones at my eardrums.
Anyway, what I found was that, when a distorting woofer was crossed over reasonably low to a "virtual" mid-high driver that did not produce any distortion itself, a fairly high level of distortion was tolerable, both before becoming audible, and even more so before becoming objectionable. However, when the frequency of the virtual XO was raised to include the midrange, too, the distortion became significantly more audible/objectionable.
The main lesson from this for me was that, assuming a given level of woofer distortion, 3-way speakers offer significant advantages over two-way designs (ok, no real news there).
The other lesson was that, in a 3-way designed on a budget, the woofer may be the best place to shave off costs, i.e. it's more important that the woofer has sufficient bass extension and SPL capability than that it produces low distortion at a given SPL, so long as it's crossed over low enough (another relevant factor here is that the price differential between competent but unexceptional woofers and high-performance woofers tends to be very large; this is not so much the case for midrange drivers or tweeters, where excellent drivers are available at fairly moderate cost).
Conversely, for two-way designs, woofer distortion performance becomes much more important (which I presume if the point you are planning to demonstrate).
I would suggest though that the trials are conducted on headphones, for multiple reasons:
OTOH, for most people at home it will be easier to determine the SPL at the listening position using speakers (to the extent that you can say there is even a single frequency-independent SPL at a given listening position in a normal room).
- they tend to have lower bass distortion and better bass extension than similarly-priced speakers (at least the sealed ones do)
- the room does not intervene to massively boost some frequencies and cut others, which may grossly affect what may or may not be audible at lower frequencies
How are you planning to model the distortion profiles and apply them to the recordings? That was the hard part for me, and the reason the whole experiment remained very informal (and until now, private).
First part is going to be to use tones and distortion profiles generated from the tests we have here on ASR.
Considering the data in the AES paper, what is your view on the importance of the specific exact volume in an informal test such as this?
Before going on to music I would like to discuss various things such as what is appropriate test content.
But are aware, that there's a rose somewhere? Lemme think where... Portuguese Amsterdam? No! Spanish Harlem!!!Not Spanish Harlem ? NNOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
Just for interest I can hear that 2.8% on a variety of speakers from high quality low distortion to cheap Bluetooth. What do you find?
Finally its not my intention to try and identify the audibility threshold limits for which you will require exacting conditions. Rather intended to be a broader look at the subject.
I don't doubt for a second that you can hear the 2.8% HD2 at 80Hz@96dB on a cheap Bluetooth speaker, as the speaker should certainly contribute another few percent distortion itself.
Just recreated your test case with two sine wave generators and in-ear headphones at high sound pressure and heard 160Hz with -31dB attenuation to the 80Hz fundamental. Would say that the noise signal was rather inaudible.
Suspect with an ABX test it will be clearer.
Then we should look at a spectrum of values.
For me, the interference signal was clearly audible and disturbing from 5-6% (-24dB).
Thus, for me 4-6% HD2 would be relevant at the earliest with an 80Hz single tone as a masker and sound pressure above 90dB.
For those who want to do an ABX test, I attach two files. 80Hz masker with interfering tone of 160Hz with -31dB attenuation.
At moderate volume (clearly not >90dB) and in-ear headphones, I got the following result:
View attachment 98794
For grins my result with your file using Oppo PM1 headphones.For those who want to do an ABX test, I attach two files. 80Hz masker with interfering tone of 160Hz with -31dB attenuation.
At moderate volume (clearly not >90dB) and in-ear headphones, I got the following result:
View attachment 98794
That's a year's precipitation where I live.in the middle very wild weather, had 400mm of rain in <24 hours.
That's a year's precipitation where I live.
I was watching a documentary where a huge salt water croc used the high water levels to gain access to a river, the croc went far upstream and then livestock started going missing until one day a guy was watering his horse and this huge croc came up and latched onto the horse... Scary stuff.Wow. You can have some of ours- it's all going down the creeks and rivers into the sea!
https://www.goldcoastbulletin.com.a...s/news-story/392c952732c34e3396934dcb91ca73e9
This photo just around the corner was taken by my neighbour. This road always floods.
View attachment 98888
View attachment 98887
I was watching a documentary where a huge salt water croc used the high water levels to gain access to a river, the croc went far upstream and then livestock started going missing until one day a guy was watering his horse and this huge croc came up and latched onto the horse... Scary stuff.